MAX1584 Datasheet, PDF (16/29 Pages) Maxim Integrated Products – 5-Channel Slim DSC Power Supplies

5-Channel Slim DSC Power Supplies
FB_
MAX1584 AUX1 AND
AUX2, MAX1585 AUX1
STEP-UP CONTROLLER
CC_
LEVEL
SHIFT
RQ
S
REFI
REF
SOFT-START
(REFI RAMPS FROM
0.85
0V TO REF IN 1024 OSC
REF
CYCLES)
FB2
MAX1585 AUX2
INVERTING CONTROLLER
CC2
DL_
LEVEL
SHIFT
RQ
DL2
S
REFI
REF
SOFT-START
(REFI RAMPS FROM
0.85
REF TO 0V IN 1024 OSC
REF
CYCLES)
CLK
CLK
OSC
OSC
FAULT
PROTECTION _ENABLE
FAULT
PROTECTION _ENABLE
FB3
MAX1584 AND MAX1585
AUX3 STEP-DOWN
CONTROLLER
CC3
LEVEL
SHIFT
RQ
DL3
S
REFI
REF
SOFT-START
(REFI RAMPS FROM
0.85
0V TO REF IN 1024 OSC
REF
CYCLES)
CLK
OSC
FAULT
PROTECTION _ENABLE
Figure 3. AUX Controller Functional Diagrams
OSC cycles, then all MAX1584/MAX1585 channels latch
off.
Maximum Duty Cycle
The MAX1584/MAX1585 auxiliary PWM controllers have
a guaranteed maximum duty cycle of 80%. In boost
designs that employ continuous current, the maximum
duty cycle limits the boost ratio so that:
1 - V_IN / V_OUT ≤ 80%
With discontinuous inductor current, no such limit exists
for the input/output ratio since the inductor has time to
fully discharge before the next cycle begins.
AUX1
AUX1 can be used for conventional DC-DC boost and
flyback designs (Figure 5). Its output (DL1) is designed
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